Dinophilidae
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| Macalister , 1876 |
Dinophilidae is tiny, the name of a family in sand gap system of living and from bacteria nourishing, other microorganisms and detritus polychaete (Polychaeta), which are found in oceans worldwide.
features
The Dinophilidae have a very small, transparent body, the segmentation of which is often only indicated by constrictions and which in Dinophilus is short and cylindrical, in Trilobodrilus and Apharyngtus, on the other hand, it is slender, elongated, flat and thread-like. On the ventral side there are usually numerous cilia of uniform size, while the cilia sit on the back in individual tufts or one to two transverse rows per segment. The head consists of the prostomium and the peristomium fused with it and is oval in Dinophilus , while in Trilobodrilus and Apharyngtus it consists of three ringlets with transverse rows of eyelashes and front with stiff sensory hairs. Antennae and palps are always missing, but a pair of eyes can be present, as in Dinophilus . The T-shaped, ventrally seated mouth is densely ciliated, and the jawless and toothless, muscular pharynx can be turned out, but is absent in the apkaryngtus . The trunk consists of 5 to 13 segments and shows no parapodia, bristles or cirrus, but it is sometimes covered with stiff hair or transverse dorsal rows of eyelashes. The pygidium with its dorsal anus is simple and round in apharyngtus, conical and pointed in dinophilus, spoon-shaped in trilobodrilus and has sensory hairs and adhesive glands with which the animals attach themselves to the substrate. The coelom is only present in the area of the gonads ( gonocoel ). The nephridia are formed as protonephridia, if present at all, but are mostly absent.
Development cycle
The Dinophilidae are separate sexes and are characterized in some species by a pronounced sexual dimorphism . In Dinophilus gyrociliatus there are gutless dwarf males who already mate the still juvenile females with their sperm in the egg cocoon by hypodermic insemination in order to enable internal fertilization. The fertilized eggs are deposited in egg cocoons or egg capsules and always develop directly into crawling worms.
Habitat and way of life
All Dinophilidae are sea creatures that live in the sand gap system , on the sediment of mud, sand or shill or between algae . Some species are euryhaline and live in estuaries , but most species inhabit the intertidal zone , and many species can be found on the algae films of marine aquariums. They move by swimming or through their eyelashes on a slime trail. The Dinophilidae feed on bacteria and other microorganisms as well as on detritus . In unfavorable conditions, some species develop permanent stages in which they spend a considerable part of their lifespan.
Systematics
The Dinophilidae family was established by Alexander Macalister in 1876 . Traditionally this family was counted among the Archiannelida and also included the genus Diurodrilus after its discovery by Adolf Remane in 1925 , but Reinhardt Kristensen and Tonny Niilonen raised them to a family of their own in 1982. By Gregory Rouse and Fredrik Pleijel the Dinophilidae became the Dorvilleidae counted. Due to their molecular genetic work presented Torsten Hugo Struck, Anja Golombek and other 2015 Dinophilidae in the clade Orbiniida , a common taxon with the Diurodrilidae , Nerillidae , Orbiniidae and Parergodrilidae , which according to the authors, in adaptation to the narrow sandy gap systems through Progenese to developed into today's dwarf forms.
Genera
The approximately 20 species of the family Dinophilidae belong to the following genera :
- Dinophilus Schmidt, 1848
- Trilobodrilus Remane, 1925
- Apharyngtus Westheide, 1971
literature
- Marian Hope Pettibone: Annelida. In: Sybil P. Parker (Ed.): Synopsis and Classification of Living Organisms , Vol. 2, pp. 1-43. McGraw-Hill, New York 1982. pp. 39f., Dinophilida, Dinophilidae.
- Torsten Hugo Struck, Anja Golombek, Anne Weigert, Franziska Anni Franke, Wilfried Westheide, Günter Purschke, Christoph Bleidorn, Kenneth Michael Halanych (2015): The Evolution of Annelids Reveals Two Adaptive Routes to the Interstitial Realm Current Biology. Current Biology 25 (15), pp. 1993-1999. DOI: 10.1016 / j.cub.2015.06.007
- Anne Weigert, Christoph Bleidorn (2016), Current status of annelid phylogeny. Organisms Diversity and Evolution 16 (2), pp. 345-362. DOI: 10.1007 / s13127-016-0265-7
Web links
- Dinophilidae . In: Lexicon of Biology , online edition, 1999.
Individual evidence
- ↑ Dinophilidae Macalister, 1876. WoRMS , 2018. Retrieved November 17, 2018.